Lesson 1 of 6 · A suit as a small spacecraft
See a spacesuit as an integrated life-support system
8 minute lesson · 3 checks along the way
Your goal for this lessonIdentify the functions that make an EVA suit more than protective clothing.
In this lesson 3 sections · 3 checks
Using archive links & definitions
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Words with a dotted underline open a short definition right here in the lesson.
Read & understand
Carry a usable environment outside
An extravehicular activity, or , takes a person outside the normal protection of a spacecraft cabin. An EVA suit must provide a pressure environment, breathing support, thermal management and communication while allowing useful work. The complete system includes the person, the garment, supporting equipment and the interfaces between them.
NASA distinguishes the from the life-support equipment. That division is useful for understanding functions, but neither part alone is the whole operational suit. An intact garment with an unavailable ventilation path is a different problem from a healthy life-support unit attached to a leaking enclosure.
Check 1 of 3
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Read & understand
Different suits have different jobs
A suit intended for use inside a vehicle during launch or entry is not automatically equipped for an independent spacewalk. Some designs depend on vehicle connections, while an EVA system may carry portable support appropriate to its tasks. Appearance and a helmet do not establish the supported environment or duration.
For a fictional comparison, suit A maintains pressure while connected to a cabin supply. Suit B has verified portable support for a defined external task. Calling both “spacesuits” is reasonable, but their demonstrated capabilities differ. Evaluate the intended use and supporting equipment before treating them as interchangeable.
Edward Higgins White II performs an EVA during Gemini 4 on June 3, 1965. His suit, chest equipment, handheld maneuvering unit and spacecraft connection show several parts of the working system. Different EVA designs distribute their support functions differently.
Look closely
Why is the visible suit garment not the complete explanation of the EVA system?
See what to notice
Breathing support, connections, equipment and the spacecraft interface also contribute to the activity. The required functions must be traced through the complete arrangement.
Check 2 of 3
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Read & understand
A useful suit supports a person doing work
The person’s size, movement and workload affect the system. Displays, controls, communications and attachment points must remain usable with the garment pressurized and gloves in place. A component can satisfy a bench test while the integrated person-and-suit arrangement makes a required action difficult.
Draw a task such as moving to a worksite and using a tool. Then trace pressure, breathing gas, cooling, power, communication and body support through that task. This reveals why the suit is often compared with a small spacecraft: its functions interact, and each must remain compatible with the work the crew member actually needs to perform.
Check 3 of 3
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Put it together
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Explore further · Optional
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Explore the evidence behind this lesson. These optional readings and videos open in a new tab.
- Read: NASA: spacewalk spacesuit basicsCompare the explanation and its assumptions with the worked example in this lesson.
- Read: NASA: what is a spacesuit?Compare the explanation and its assumptions with the worked example in this lesson.
- Read: NASA: spacesuit engineering and testingCompare the explanation and its assumptions with the worked example in this lesson.